Using radio frequency identification with transaction-specific correlator values written on transaction receipts to detect and/or prevent theft and shoplifting

ABSTRACT

Techniques are disclosed for detecting shoplifting or theft, particularly in a retail environment, using radio-frequency identification (“RFID”). Preferred embodiments leverage RFID tags on merchandise and RFID data that is written at the point of sale on the merchandise-borne RFID tags themselves, on the customer&#39;s receipt, or both. Some embodiments also leverage RFID tags on customer identification or “loyalty” cards. After writing RFID data on the merchandise-borne tags and/or receipt, a matching operation is performed at an RFID reader when the shopper and his merchandise exit the premises, in order to determine whether the shopper has paid for the items in his possession.

BACKGROUND OF THE INVENTION RELATED INVENTIONS

The present invention is related to the following commonly-assignedco-pending applications, which were filed concurrently herewith andwhich are hereby incorporated herein by reference: U.S. patent Ser. No.10/665,282, titled “Using Radio Frequency Identification to Detectand/or Prevent Theft and Sboplifking”; U.S. patent Ser. No. 10/666,483,titled “Using Radio Frequency Identification with Customer Loyalty Cardsto Detect and/or Prevent Theft and Shoplifting”; U.S. patent Ser. No.10/666,287, titled “Using Radio Frequency Identification withTransaction-Specific Correlator Values to Detect and/or Prevent Theftand Shoplifting”; and U.S. patent Ser. No. 10/666,700, titled “UsingRadio Frequency Identification with Transaction Receipts to Detectand/or Prevent Theft and Shoplilting”.

1.Field of the Invention

The present invention relates to radio-frequency identification (“RFID”)technology, and deals more particularly with techniques for leveragingRFID technology with transaction-specific correlator values written ontransaction receipts to detect and/or prevent theft and shoplifting.

2. Description of the Related Art

Theft and shoplifting are problems in many environments. For retailbusinesses, for example, billions of dollars are lost every year toshoplifting. Several techniques exist to combat theft in the retailenvironment. As one example, some retailers station an employee at thestore exit to visually verify that the merchandise in the customer'spossession matches an itemized receipt that was issued at the point ofsale. Of course, this approach is expensive for the retailer, and isoften intimidating and humiliating for honest customers. Otherapproaches, also not cost-effective, include stationing employees toguard the merchandise, chaining high-value items to display shelves orplacing them in locked display cases, and electronic surveillance(“EAS”).

Many technologies have been employed for EAS. The basic principle behindmost prior-art EAS systems includes using a transmitter to create anelectromagnetic field across the store's exit area and a receiver thancan detect variations in the field. Small tuned circuits or magneticmaterial inside security tags that pass through the exit modify thefield enough for the receiver to detect the change and activate analarm. The retailer attaches the tags to high-risk items, and the EASnotifies him or her when a tag passes through the exit field. Thesecurity tag must be removed or deactivated at the point of sale toprevent the alarm from sounding. See “Stop! Thief” by Warren Webb, EDN,Jun. 21, 2001, pp. 52, 54, 56, for a review of prior-art EAS systems.

Passive EAS systems in use today typically operate at 8.2 MHZ, 9.5 MHZ,and other frequencies. EAS tags for garments may be detached at thepoint of sale using a special tool. EAS tags on smaller items, alsocalled disposable labels, are designed to remain on the item but must bedeactivated (detuned) at the point of sale. This is done by passing thetagged item near a strong electromagnetic filed, which changes thetuning of the passive antenna in the tag by destroying a fusible link,thus modifying the return signal detected when the item passes near thereceiver.

The tags used by these types of prior-art EAS systems are completelypassive.

More recently, a new technology called Radio Frequency Identification(“RFID”) has been introduced for labeling and tracking items ofmerchandise from manufacturing through distribution and retail sale.RFID differs from passive EAS technologies in several important ways. AnRFID tag includes both passive elements (an antenna) and active elements(a read-write data memory, control circuitry, and a radio frequencytransponder). RFID tags are typically not self-powered, but may receivetheir power via capacitative coupling from an external radio frequencysource. When brought into proximity with an RFID reader at a typicaleffective distance of about 1 centimeter to 5 meters (depending on thetype of tag), the RFID tag receives sufficient power to enable clockingthe semiconductor and analog portions comprising the transponder,control circuits, and data memory through enough clock cycles that thetag can return the data bits from its memory as a digitally-encoded RFsignal. This is advantageous because the tag can be read (or written)from a distance without the necessity of line-of-sight, as had beenrequired to read a bar code with a laser scanner.

RFID technology has generally been utilized for inventory control (e.g.,in a warehouse, manufacturing, or distribution facility) and for itemidentification at the point of sale as an improvement over today'snearly ubiquitous laser-scanned bar codes. Several large retailers haveindicated a desire to begin using RFID tagging on all their merchandise.RFID tags can be created using relatively inexpensive manufacturingtechniques: the antenna portion can be printed on packaging materialwith conductive carbon ink, and the semiconductor portion—as small as 3millimeters square—can be mounted to the antenna with glue. The cost ofRFID tags is expected to decline to the point of being cost-effectiveeven on small-value retail items. Thus, it can be assumed that in thenear future, RFID tags on merchandise will become nearly ubiquitous.

The use of RFID to deter theft has been suggested in several contexts.Notably, early RFID literature suggested that RFID could be used forimproved inventory control, thereby preventing employees from stealingitems from the store's inventory. The literature also suggested thatRFID could prevent theft in the distribution chain between themanufacturer and retailer, by actively monitoring inventory in trucksand shipping containers to ensure that merchandise was not diverted tounintended destinations. Commonly-assigned, co-pending U.S. patentapplication Ser. No. 09/790,104 (filed on Feb. 21, 2001), entitled“Method to Address Security and Privacy Issues of the Use of RFIDSystems to Track Consumer Products” (which is hereby incorporated hereinby reference), discussed techniques for secure electronic labeling byoverwriting RFID tags at the point of sale and by placing control bitsinto the RFID data memory, in order to prevent an unscrupulous storeemployee from reprogramming the RFID tag of an expensive item with datarepresenting an inexpensive item, in order to pay a lower price for theexpensive item.

The read-write data memory in today's RFID tags is non-volatile andtypically has a capacity of 5 to 256 bytes. The antenna in RFID tags canbe printed on a product's packaging using conductive ink, as notedabove. Or, rather than placing the tag on the packaging, it may beincorporated into the product (for example, by sewing an RFID tag into agarment, placing an RFID tag on a page within a book, and so forth). Thememory typically stores an “Electronic Product Code” or “EPC”, acounterpart of the bar code, that assigns a searchable number to eachobject. The EPC identifies a consumer product individually, not just bytype. Present versions of the code use 96 bits of information, whichcomprises an 8-bit header, two sets of 24 bits that identify themanufacturer and the product type (respectively), and a 40-bit serialnumber. Ninety-six bits encode enough information to uniquely identifytrillions of objects. See “Beyond the Bar Code” and companion article“What's My Number” by Charlie Schmidt, Technology Review Magazine, March2001, pp. 80–85.

Prior art techniques are deficient in several respects. Having anemployee inspect each shopper's merchandise is not only expensive forthe employer and embarrassing for the shoppers, as noted above, it isalso prone to human error. Existing passive EAS technology leaves roomfor a number of improvements and adaptations. RFID tagging ofmerchandise is coming into use in retail environments, but as presentlyutilized this technology does not avoid the need to also tag thearticles with traditional EAS tags for theft detection, or to disablethe RFID tag at the point of sale as is generally done with passivedisposable EAS tags. It is desirable to continue utilizing the RFID tagas a data transponder, without destroying the tag or deleting its datamemory, after an item containing the tag has been purchased at a pointof sale. It is also desirable to determine, on the spot, whether an itemhas been paid for, even if a transaction database in which transactionsare recorded is unavailable. The present invention avoids deficienciesof the prior art, while providing effective techniques for shopliftingand theft detection.

SUMMARY OF THE INVENTION

An object of the present invention is to provide improved techniques forshoplifting and theft detection.

Another object of the present invention is to provide techniques fordetecting shoplifting using RFID technology with transaction-specificcorrelator values written on transaction receipts.

A further object of the present invention is to use RFID technology toreduce lost revenue caused by shoplifting.

Yet another object of the present invention is to enable detection ofshoplifting even though a transaction database in which productpurchases are recorded is (at least temporarily) unavailable.

Other objects and advantages of the present invention will be set forthin part in the description and in the drawings which follow and, inpart, will be obvious from the description or may be learned by practiceof the invention.

To achieve the foregoing objects, and in accordance with the purpose ofthe invention as broadly described herein, the present invention may beprovided as methods, systems, and/or computer program products. In oneaspect, the present invention provides techniques for preparinginformation usable in detecting shoplifting, comprising: creating aunique correlator value, for a current transaction, as a function of oneor more values; storing the unique correlator value in an RFID tagaffixed to each of one or more items presented for purchase in thecurrent transaction; and storing the unique correlator value on areceipt prepared for the current transaction. The unique correlatorvalue on the receipt may be stored in an RFID tag affixed thereto.

In another aspect, the present invention provides techniques fordetecting potential theft, comprising: reading, from a transactionreceipt, a correlator value; searching, in an RFID tag affixed to eachor one or more items possessed by a shopper who also possesses thetransaction receipt, for the correlator value; and concluding that atleast some of the one or more items possessed by the shopper were notpaid for if the correlator value is not located in the search. Theunique correlator value on the transaction receipt may be stored in anRFID tag affixed thereto.

The reading may be performed by a human, and a human-readablerepresentation of results of the search may be presented for use in theconclusion.

The technique may further comprise: initially creating the correlatorvalue as a unique correlator value for a current transaction, using asinput one or more values; previously storing the initially-createdcorrelator value in an RFID tag affixed to each of one or more itemspresented for purchase in the current transaction, prior to operation ofthe search; and storing the unique correlator value on the transactionreceipt prepared for the current transaction, prior to reading thecorrelator value.

In one approach, if the correlator value of a particular item reflects aprevious transaction, then that item is preferably treated as havingbeen paid for. In another approach, if selected ones of the items werein the shopper's possession when the shopper entered an establishment inwhich a transaction reflected by the transaction receipt was conducted,then those selected ones are preferably treated as having been paid for.In still another approach, each item that was in the shopper'spossession when the shopper entered the establishment is remembered, andthe search and conclusion do not apply to the remembered items.

The present invention will now be described with reference to thefollowing drawings, in which like reference numbers denote the sameelement throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a representative RFID tag, according to the priorart;

FIG. 2 illustrates a customer loyalty card, according to the prior art;

FIGS. 3A and 3B, 5A and 5B, 7A and 7B, 9A and 9B, and 11A and 11Billustrate components involved in several preferred embodiments of thepresent invention; and

FIGS. 4A and 4B, 6A and 6B, 8A and 8B, 10A and 10B, and 12A and 12Bprovide flowcharts illustrating logic that may be used when implementingseveral preferred embodiments of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention provides improved techniques for detectingshoplifting (referred to hereinafter equivalently as theft),particularly in a retail environment. Preferred embodiments leverageRFID tags on merchandise and RFID data that is written at the point ofsale on the merchandise-borne RFID tags themselves, on the customer'sreceipt, or both. Some embodiments also leverage RFID tags on customeridentification or “loyalty” cards. After writing RFID data on themerchandise-borne tags and/or receipt, a matching operation is performedat an RFID reader when the shopper and his merchandise exit thepremises, in order to determine whether the shopper has paid for theitems in his possession.

RFID tags are expected to become nearly ubiquitous, as stated earlier.In many cases, an RFID tag bears an EPC that uniquely identifies aproduct (including product type, serial number, etc.), as describedearlier. Alternatively, an RFID tag of the prior art may bear an itemSKU (“stock-keeping unit”) and a unique item serial number. An SKU is anidentifier used for categorizing products, for example by item type. Theserial number may be globally unique, or unique within the SKU number. Acombination of SKU and serial number may therefore be used to uniquelyidentify a particular item of that particular type. When using either anEPC or an SKU with serial number, this information is stored in thesmall memory area on the RFID tag. When power is supplied to the RFIDtag's antenna from an RFID reader, as described above, the informationstored in the memory area can be read and transmitted. Several preferredembodiments of the present invention write additional information intothis memory area, as will be described.

A representative RFID tag 100 of the prior art is illustrated in FIG. 1,showing a coiled antenna 120 (which in this example takes on a generallysquare shape) embodied on some type of substrate 1 10. Customer loyaltycards are used in several embodiments of the present invention, and thephysical appearance of a representative loyalty card of the prior art isshown in FIG. 2. Loyalty cards of the prior art store a customer ID in amachine-readable magnetic strip which is typically scanned at the pointof sale, and are used by many different types of stores to trackinformation such as customer buying habits. Some embodiments of thepresent invention attach an RFID tag to a customer loyalty card so thecustomer ID data can be read from the card via an RFID reader.

In each preferred embodiment of the present invention, operations areinitially performed at the point of sale to identify the items selectedby the shopper for purchase. Additional operations are then performed aseach shopper exits the store, where these later operations are directedtoward verifying information provided by the operations that wereperformed at the point of sale.

In a first preferred embodiment, a checksum is used in detectingpotential theft. Components leveraged by this embodiment are showngenerally in FIGS. 3A and 3B, and flowcharts depicting logic that may beused in an implementation of this embodiment are shown in FIGS. 4A and4B.

A shopper selects some number of items, represented by element 300 inFIG. 3A, and presents these items for checkout at a point of sale (Block400 of FIG. 4A). At the point of sale, an RFID reader 305 reads anRFID-readable identifier borne on each item presented for purchase(Block 405). A checksum generation component 310 (which may be embodiedwithin the RFID) reader) generates a checksum of data from theRFID-readable identifiers (Block 410). The data used in generating thechecksum may comprise the item's EPC, its SKU, its unique item serialnumber, some combination thereof, or any other data or data combinationfrom the RFID) tag, provided that the data used for each particular itemserves to identify tat item. (Any suitable checksum algorithm may beused without deviating from the inventive concepts of the presentinvention.)

Next, the generated checksum is written (Block 415) by an RFID writercomponent 315 (which may be embodied within the RFID reader and/orchecksum generator components 305, 310) onto a sales receipt 320 in anRFID-readable form. Preferably, the checksum is written on the receiptusing a passive RFID print-on-demand technology. As an example of thisprint-on-demand approach, an antenna and memory chip may be applied tothe receipt at the point of sale. Alternatively, a pre-manufactured RFIDreceipt card may be customized at the point of sale by writing data intoits memory. (For ease of reference, discussions hereinafter of writingto a “receipt” are in terms of using a printed sales receipt rather thana receipt card or other form of receipt, although this is for purposesof illustration and not of limitation.) A preferred manner of locatingthis RFID-readable checksum on the sales receipt 320 is to position thechecksum as shown at element 322, beneath the conventional printout 321that lists the individual items and pricing information. Alternatively,the RFID-readable checksum may be placed at another location on thereceipt.

It is expected that a print-on-demand capability for RFID tags will berelatively inexpensive in the near future. In the general case,“print-on-demand” capability refers to applying an RFID tag to an itemat some time following an item's manufacture. In another aspect, thememory component is applied to an item during the manufacturing process,and the antenna is subsequently applied using print-on-demandtechnology. In an aspect leveraged by this first preferred embodiment,the entire RFID tag is printed on demand on a sales receipt that hasbeen printed or otherwise generated at the point of sale and thecomputed checksum is written into this tag's data memory.

Referring now to FIGS. 3B and 4B, as the shopper exits the premisescarrying merchandise 330 and sales receipt 320, he passes an RFID reader335 (Block 450) which non-intrusively reads the RFID-readableidentifiers on the exiting merchandise and the checksum on the receipt(Block 455). A checksum generator component 340, which performs the samecomputations as checksum generator component 310 of FIG. 3A (and whichmay be embodied within the RFID reader 335), then computes the checksumanew (Block 460) over the data read by RFID reader 335 from theshopper's items 330. A checksum comparison component 345 then comparesthe two checksums (Block 465) to determine whether they match (Block470). If the items 330 in the shopper's possession at checkout are thesame items 300 that were presented and purchased at the point of sale,then the checksums will be identical, and the test in Block 470 willhave a positive result, indicating that there is no theft (Block 475).

Otherwise, when the checksums do not match, this is a potential theftsituation (Block 480). The shopper may be concealing items that weredetected by the RFID reader 335, but which were not presented at thepoint of sale and are therefore not reflected in the checksum 322 on thereceipt. Or, the shopper may have substituted a more expensive item, orseveral of the same item, in place of one paid for. Conventional meansare preferably used to deal with this potential theft, such astriggering an alarm unit 350, notifying store personnel, and/or stoppingthe shopper and the merchandise from exiting the premises.

In a second preferred embodiment, a customer loyalty card is used indetecting potential theft. According to this embodiment, the loyaltycard is augmented to include an RFID tag or component, where the tag'smemory stores a unique customer number (or, equivalently, otherinformation that uniquely identifies this particular customer) that canbe read with an RFID reader. (Note that while discussions herein referprimarily to using RFID “tags”, this is not meant to limit the presentinvention to use with a particular physical form of RFID implementation.RFID tags may be more generally referred to as transponders. An RFID tagmay be embedded into an item, and it is therefore not necessary that thephysical embodiment of the RFID components resemble a tag.) Componentsused in this second preferred embodiment are shown generally in FIGS. 5Aand 5B, and flowcharts depicting logic that may be used in animplementation of this embodiment are shown in FIGS. 6A and 6B.

In this second preferred embodiment, a shopper presents his loyalty card500, containing the RFID tag 501, along with his selected items 530 atthe point of sale (Block 600 of FIG. 6A). An RFID reader 510 reads thecustomer number from the loyalty card (Block 610). An RFID writer 520(which may be embodied within the RFID reader) then writes this customernumber (Block 620) to the RFID tag of each item 531, 532, 533 purchased.

Referring now to FIGS. 5B and 6B, as the shopper exits the premises withhis loyalty card 500 and merchandise 540, he passes an RFID reader 550(Block 650) which non-intrusively reads the RFID tag from the loyaltycard and the RFID tag from each item (Block 660). A customer numbercomparison component 560 (which may be embodied within the RFID reader550) compares the customer number from each item (Block 670) with thecustomer number from the loyalty card to determine whether they match(Block 680). If the numbers do not match on any of the comparisons(Block 695), then this is a potential theft situation, and conventionalmeans may be used as described above (such as triggering an alarm unit570). Otherwise, if the customer number matches on each comparison(Block 690), then this is a not a theft situation.

In a third preferred embodiment, illustrated in FIGS. 7A and 7B (showingcomponents) and FIGS. 8A and 8B (depicting flowcharts), a uniquecorrelator is used in detecting potential theft. The correlator iscreated for each sales transaction, using any suitable data forgenerating a unique value. Examples of data that may be used in thisprocess are shown generally at 700 of FIG. 7A, and include the currentdate and time, the register number of a cash register or otherpoint-of-sale device, a transaction identifier, a customer numberconcatenated with a counter that is incremented specifically for thiscustomer, and so forth. As another example, the correlator might beformed simply by using a counter which is initialized to a particularvalue upon first use and is then incremented for subsequent purchases.The correlator creating component is shown at 710, and may be embodiedin the point-of-sale device (or in the RFID writer 720).

When the shopper presents his items 730 for purchase (Block 800), thecorrelator is generated (Block 810) and written (Block 820) by the RFIDwriter 720 into the RFID tag of each purchased item 730. The samecorrelator is also written (Block 830) onto the sales receipt 740,preferably using RFID print-on-demand technology as discussed earlier.In this embodiment, the sales receipt 740 preferably includesconventional information 741, such as an itemized list of purchases, andthe RFID-readable correlator appears in a separate location 742 (such asfollowing the conventional information 741).

Referring now to FIGS. 7B and 8B, as the shopper exits the premisescarrying merchandise 750 and sales receipt 740, he passes an RFID reader760 (Block 850) which non-intrusively reads the correlators from theRFID tags of the exiting merchandise and the sales receipt (Block 860).At Block 870, a comparison is performed by a correlator comparisoncomponent 770 (which may be embodied within the RFID reader 760),comparing each individual item's correlator to the correlator read fromthe sales receipt. Block 880 tests whether these correlators match. Ifso, then this is not a theft situation (Block 890). Otherwise, when thecorrelators do not match (including the case where the shopper possessesitems having no correlator), this is a potential theft situation (Block895). Conventional means are preferably used to deal with this potentialtheft, such as triggering an alarm unit 780 and so forth.

In an optional aspect of this third preferred embodiment, instead of (orin addition to) writing the correlator on the receipt using RFIDtechnology, the correlator may be written in another manner. Forexample, a textual representation of the correlator may be printed onthe receipt, or a machine-readable representation (such as a barcodeversion or an optical character recognition, or “OCR”, version) might beused. In this aspect, when the shopper is exiting the premises, a humanor a different automated component performs the reading of sales receipt740 and the comparison of its correlator to the correlators read fromthe items in the shopper's possession.

It may happen that a shopper buys items from mote than one merchant, andthereibre has some items in his possession that have RFID tags matchingthe correlator on the sales receipt as well as other items that do nothave this conelator. Or, the shopper may have items in his possessionthat were purchased from this merchant at an earlier dine. Such itemswill therefore not have a correlator matching the correlator on thepresent sales receipt. A preferred approach for dealing with thissituation is for the retailer to maintain a database of this merchant'spreviously-generated correlator, and to include a comparison againstvalues in this database prior to concluding that a non-match (Block 880of FIG. 8B) is a potential theft. For example, if a shopper has an itemwith a correlator that does not match his receipt, perhaps this is acorrelator generated by the retailer next door. In this case, thecorrelator will not be found in the current retailer's database, andwill not be considered as a theft. On the other hand, if an itempossessed by the shopper has a correlator that does not match hisreceipt but this item's correlator is found in the correlator database,then this is an item previously purchased from this merchant (and it isnot a theft).

A fourth preferred embodiment, shown in FIGS. 9A and 9B, 10A and 10B, issimilar to the third preferred embodiment, except that the correlator isnot written to the sales receipt. Again, the correlator is unique, andis created for each sales transaction using input data shown generallyat 900 of FIG. 9A. The correlator creating component is shown at 910,and as in the third preferred embodiment, this component may be embodiedin the point-of-sale device (or in the RFID writer 920).

In this fourth preferred embodiment, when the shopper presents his items930 for purchase (Block 800), the correlator is generated (Block 1010)and written (Block 1020) by the RFID writer 920 into the RFID tag ofeach purchased item 930. When the shopper exits the premises, asdepicted in FIGS. 9B and 10B, the merchandise 950 he is carrying passesan RFID reader 960 (Block 1050) which non-intrusively reads thecorrelators from the RFID tags (Block 1060). Now, however, a correlatorcomparing component 980 (which may be embodied within the RFID reader960) makes a comparison (Block 1070) among the correlators of thevarious items. If the correlators all match each other (Block 1080),then this is not a theft (Block 1085). If any correlators are different,however, then a database 970 is preferably consulted to determinewhether a non-matching correlator reflects a previous purchase (Block1090). If so, then the shopper may have purchased this item from theretailer on an earlier date. For example, if the non-matching correlatoris stored in the RFID tag of a clothing article which the shopperpreviously purchased from this retailer and is now wearing in theretailer's store, this is not a theft. However, if the RFID tagindicates that the item is from this retailer's inventory but noprevious purchase of this item is recorded (including a current purchasewhich would have written a matching correlator in the item's RFID tag),then this is potentially an attempted theft (Block 1095) and the alarmunit 990 is preferably triggered.

In one aspect of this fourth embodiment, items that are in the shopper'spossession upon entry to the retailer's premises and that have RFID tagson them are tracked. When the shopper exits the premises, the comparisonamong correlators (Block 1070) excludes those items which the shopperbrought onto the premises. The items that are potentially stolen arethen those items that (1) the shopper did not bring with him, and (2)have either no correlator or a correlator that does not match the othercorrelators.

Alternatively, if the items brought onto the premises by the shopper arenot known, then the comparison among correlators (Block 1070) preferablyexcludes any items which can be determined (e.g., by consulting thedatabase 970) to be previous purchases, as described above.

In a fifth preferred embodiment, which may be implemented usingcomponents shown generally in FIGS. 11A and 11B and logic as depicted inFIGS. 12A and 12B, information written on a receipt (not necessarilywith an RFID tag) is used in detecting potential theft.

In this preferred embodiment, a shopper presents his selected items 1100at the point of sale (Block 1200 of FIG. 12A). An RFID reader 1110 readsinformation from each item's RFID tag (Block 1210). Preferably, the EPCis read, although other information from the RFID tag may be usedwithout deviating from the scope of the present invention. Thus,subsequent discussions of this fifth preferred embodiment refer to theEPC by way of illustration but not of limitation.

The EPC for each item is written in machine-readable form onto thereceipt 1130 (Block 1220) by an appropriate writer component 1120. AnRFID form may be used, in which case the writer component 1120 is anRFID writer that preferably writes onto the receipt usingprint-on-demand technology of the type described above. Or, a barcode,OCR, magnetic stripe, or other machine-readable format of the prior artmay be used. One approach that may be used for writing the EPC to thereceipt is to position the EPC information in a location 1132 separatefrom the conventional printed information 1131. When multiple items havebeen purchased, the EPC information is preferably encoded as anenumerated list (where each item's EPC may be distinguished from anotherwith a special delimiter or by simply using a fixed-lengthrepresentation in each case).

As the shopper exits the premises (referring now to FIGS. 11 B and 12B),he passes an RFID reader 1160 (Block 1250) which non-intrusively readsthe RFID tag from each item 1150 (Block 1260). The sales receipt 1130 ispassed through an appropriate scanner 1170 (Block 1270). A comparisoncomponent 1180 then compares (Block 1280) the EPCs read by the RFIDreader with the enumerated EPCs read from the receipt. If the EPCs allmatch (Block 1285), then this is not a theft (Block 1290). Otherwise, apotential theft is indicated (Block 1295), and an alarm unit 1190 may betriggered, etc.

As has been demonstrated, the present invention provides advantages overprior art theft detection techniques by leveraging RFID technology innovel ways. The techniques disclosed herein use relatively lightweightcomputations, and may therefore be carried out quite efficiently.

The present invention may also be used to thwart other types of theft.For example, assume that a customer who just purchased a collection ofitems and obtained a receipt leaves the store, only to return a fewminutes later and select the same collection of items, hoping the priorreceipt will enable him to leave the store without paying for the secondcollection of items. Embodiments of the present invention will detectthe new collection of items as not having been purchased, since theitems do not bear the customer's loyalty card number (in the secondpreferred embodiment, described with reference to FIGS. 5A and 5B), theitems do not bear a correlator matching the correlator on the receipt(in the third embodiment, described with reference to FIGS. 7A and 7B),the items do not bear identical correlators (in the fourth preferredembodiment, described with reference to FIGS. 9A and 9B), or the items'unique EPC numbers are not enumerated on the receipt (in the fifthpreferred embodiment, described with reference to FIGS. 11A and 11B).

It should be noted that while preferred embodiments of the presentinvention have been described with reference to use in a retailenvironment, the disclosed techniques may also be leveraged in otherenvironments where it is desirable to detect concealment of items.

Embodiments of the present invention may also unobtrusively scanRFID-readable items on the customer's person when he/she enters thestore, retain such information for the duration of the customer'sshopping session, and account for it as the customer leaves the store,since it is understood that items carried onto the premises by thecustomer and then subsequently removed are not being stolen. The EPCs orother identifying data borne on such pre-purchased items can be deletedfrom the list of items scanned upon exit, so that their departure fromthe store will not signal a potential theft.

Embodiments of the present invention, including those described above,may analyze information stored in an RFID tag to distinguish whetheritems carried by the shopper are from the inventory of the retailer inwhose store the shopper is presently located. In this manner, itemspurchased elsewhere (or at earlier times) will be omitted from thetheft-detection operations performed as the shopper is exiting theretailer's premises. (For example, such items will be omitted from thechecksum computation performed in the first preferred embodiment, thecorrelator comparison of the third and fourth preferred embodiments, andso forth.)

The disclosed techniques may be used advantageously in methods of doingbusiness, for example by providing improved item checkout and salesreceipt comparison services. As an example of how this may be provided,a service may be offered that (1) captures information at the point ofsale, (2) performs theft detection at the exit from the premises, and(3) charges a fee. The fee might be charged uniformly for eachtransaction, or a fee might be assessed for each intercepted theft. Ineither case, the fee might be based on number of transactions performed,on the number of items in each transaction, or the total value of thetransaction. Or, the fee might be assessed using as a subscription modelwhereby retailers pay a fixed fee for a periodic interval. In addition,an advantageous service may be provided with either the informationcapturing or the theft detection aspect, without the other, in caseswhere other means are available for that other aspect.

Commonly-assigned, co-pending U.S. patent application Ser. No.09/790,104 (filed on Feb. 21, 2001), entitled “Method to AddressSecurity and Privacy Issues oft. Use of RFID Systems to Track ConsumerProducts”, which was briefly discussed above, discloses techniques toprevent global tracking of people and the items they have purchasedcontaining RFID tags, in addition to techniques for using RFIDtechnology to prevent tampering of product information stored in RFIDtags and to prevent pricing mistakes made at the point of sale.Commonly-assigned, co-pending U.S. patent application Ser. No.09/847,889 (filed on May 3, 2001), entitled “Identification and Trackingof Persons Using RFID-Tagged Items”, discloses techniques for using RFIDtechnology to identify or characterize people, based on the RFID tagspresent in items being carried by that person at a point in time. If aprior-purchase database is provided with information about which personbought particular uniquely-identified items in the past, then the RFIDtags may be ed to locate information in the database twill identify theperson currently carrying the items. Otherwise, the person can becharacterized based upon the types of items he is currently carrying (asdetermined by reading the RFID tags of the items). Commonly-assigned,co-pending U.S. patent application Ser. No. 10/612,251 (filed on Jul. 2,2003), entitled “Object Matching via RFID”, discloses techniques forusing RFID technology to track and match objects, when the RFID tags ofthese objects have been programmed with data suitable for indicatingthat the items are in association with one another. Thesecommonly-assigned inventions are hereby incorporated herein by referenceas if set forth filly.

As will be appreciated by one of skill in the art, embodiments of thepresent invention may be provided as methods, systems, or computerprogram products. Embodiments of the present invention may be providedusing hardware, software, or a combination thereof. Furthermore, thepresent invention may take the form of a computer program product whichis embodied on one or more computer-readable storage media (including,but not limited to, disk storage, CD-ROM, optical storage, and so forth)having computer-readable program code or instructions embodied therein.

The present invention has been described with reference to flowchartillustrations and/or block diagrams usable in methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions,which may be stored on one or more computer-readable media, may beprovided to a processor of a general purpose computer, special purposecomputer, embedded processor, or other programmable data processingapparatus to produce a machine, such that the instructions, whichexecute via the processor of the computer or other programmable dataprocessing apparatus, create computer-readable program code means forimplementing the functions specified in the flowchart and/or blockdiagram block or blocks.

These computer program instructions may also be stored in acomputer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including instruction meanswhich implement the function specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer orother programmable data processing apparatus to cause a series ofoperational steps to be performed on the computer or other programmableapparatus to produce a computer implemented process such that theinstructions which execute on the computer or other programmableapparatus provide steps for implementing the functions specified in theflowchart and/or block diagram block or blocks.

While several preferred embodiments of the present invention have beendescribed, additional embodiments as well as variations andmodifications in the disclosed embodiments may occur to those skilled inthe art once they learn of the basic inventive concepts. Therefore, itis intended that the appended claims shall be construed to includepreferred embodiments and all such variations and modifications as fallwithin the spirit and scope of the invention.

1. A method of preparing information usable in theft detection using radio frequency identification (“RFID”) technology, comprising steps of: creating a unique correlator value, for a current transaction, as a function of one or more values; storing the unique correlator value in an RFID tag affixed to each of one or more items presented for purchase in the current transaction; and storing the unique correlator value on a receipt prepared for the current transaction.
 2. The method according to claim 1, wherein the unique correlator value on the receipt is stored in an RFID tag affixed thereto.
 3. A method of detecting potential theft using radio frequency identification (“RFID”) technology, comprising steps of: reading, from a transaction receipt, a correlator value; searching, in an RFID tag affixed to each of one or more items possessed by a shopper who also possesses the transaction receipt, for the correlator value; and concluding that at least some of the one or more items possessed by the shopper were not paid for if the correlator value is not located in the searching step.
 4. The method according to claim 3, wherein the correlator value on the transaction receipt is stored in an RFID tag affixed thereto.
 5. The method according to claim 3, wherein the reading step is performed by a human, and wherein a human-readable representation of a result of the searching step is presented for use in the concluding step.
 6. The method according to claim 3, further comprising the steps of: initially creating the correlator value as a unique correlator value for a current transaction, using as input one or more values; previously storing the initially-created correlator value in an RFID tag affixed to each of one or more items presented for purchase in the current transaction, prior to operation of the searching step; and storing the unique correlator value on the transaction receipt prepared for the current transaction, prior to operation of the reading step.
 7. The method according to claim 3, wherein the concluding step concludes that selected ones of the possessed items were paid for if the correlator value of the selected ones reflects a previous transaction.
 8. The method according to claim 3, wherein the concluding step concludes that selected ones of the possessed items were paid for if those selected ones were in the shopper's possession when the shopper entered an establishment in which a transaction reflected by the transaction receipt was conducted.
 9. The method according to claim 3, further comprising the step of remembering each item that was in the shopper's possession when the shower entered an establishment in which a transaction reflected by the transaction receipt was conducted, and wherein the searching and concluding steps do not apply to the remembered items.
 10. A system for preparing information usable in theft detection using radio frequency identification (“RFID”) technology, comprising: means for creating a unique correlator value, for a current transaction, as a function of one or more values; means for storing the unique correlator value in an RFID tag affixed to each of one or more items presented for purchase in the current transaction; and means for storing the unique correlator value on a receipt prepared for the current transaction.
 11. The system according to claim 10, wherein the unique correlator value on the receipt is stored in an RFID tag affixed thereto.
 12. A system for detecting potential theft using radio frequency identification (“RFID”) technology, comprising: means for reading, from a transaction receipt, a correlator value; means for searching, in an RFID tag affixed to each of one or more items possessed by a shopper who also possesses the transaction receipt, for the conelator value; and means for concluding that at least some of the one or more items possessed by the shopper were not paid for if the correlator value is not located by the means for searching.
 13. The system according to claim 12, wherein the correlator value on the transaction receipt is stored in an RFID tag affixed thereto.
 14. The system according to claim 12, wherein the means for reading is performed by a human, and wherein a human-readable representation of a result of the means for searching is presented for use by the means for concluding.
 15. The system according to claim 12, further comprising: means for initially creating the correlator value as a unique correlator value for a current transaction, using as input one or more values; means for previously storing The initially-created correlator value in an RFID tag affixed to each of one or more items presented for purchase in the current transaction, prior to operation of the means for searching; and means for storing the unique correlator value on the transaction receipt prepared for the current transaction, prior to operation of the means for reading.
 16. The system according to claim 12, wherein the means for concluding concludes that selected ones of the possessed items were paid for if the correlator value of the selected ones reflects a previous transaction.
 17. The system according to claim 12, wherein the means for concluding concludes that selected ones of the possessed items were paid for if those selected ones were in the shopper's possession when the shopper entered an establishment in which a transaction reflected by the transaction receipt was conducted.
 18. The system according to claim 12, further comprising means for remembering each item that was in the shopper's possession when the shopper entered an establishment in which a transaction reflected by the transaction receipt was conducted, and wherein the means for searching and means fur concluding do not apply to the remembered items.
 19. A computer program product for preparing information usable in theft detection using radio frequency identification (“RFID”) technology, the computer program product embodied on one or more computer-readable media and comprising: computer-readable program code means for creating a unique correlator value, for a current transaction, as a function of one or more values; computer-readable program code means for storing the unique correlator value in an RFID tag affixed to each of one or more items presented for purchase in the current transaction; and computer-readable program code means for storing the unique correlator value on a receipt prepared for the current transaction.
 20. The computer program product according to claim 19, wherein the unique correlator value on the receipt is stored in an RFID tag affixed thereto.
 21. A computer program product for detecting potential theft using radio frequency identification (“RFID”) technology, the computer program product embodied on one or more computer-readable media and comprising: computer-readable program code means for reading, from a transaction receipt, a correlator value; computer-readable program code means for searching, in an RFID tag affixed to each of one or more items possessed by a shopper who also possesses the transaction receipt, for the correlator value; and computer-readable program code means for concluding that at least some of the one or more items possessed by the shopper were not paid for if the correlator value is not located by the computer-readable program code means for searching.
 22. The computer program product according to claim 21, wherein the correlator value on the transaction receipt is stored in an RFID tag affixed thereto.
 23. The computer program product according to claim 21, wherein the computer-readable program code means for reading is performed by a human, and wherein a human-readable representation of a result of the computer-readable program code means for searching is presented for use by the computer-readable program code means for concluding.
 24. The computer program product according to claim 21, further comprising: computer-readable program code means for initially creating the correlator value as a unique correlator value for a current transaction, using as input one or more values; computer-readable program code means for previously storing the initially-created correlator value in an RFID tag affixed to each of one or more items presented for purchase in the current transaction, prior to operation of the computer-readable program code means for searching; and computer-readable program code means for storing the unique correlator value on the transaction receipt prepared for the current transaction, prior to operation of the computer-readable program code means for rending.
 25. The computer program product according to claim 21, wherein the computer-readable program code means for concluding concludes tat selected ones of the possessed items were paid for if the correlator value of the selected ones reflects a previous transaction.
 26. The computer program product according to claim 21, wherein the computer-readable program code means for concluding concludes that selected ones of the possessed items were paid for if those selected ones were in the shopper's possession when the shopper entered an establishment in which a transaction reflected by the transaction receipt was conducted.
 27. The computer program product according to claim 21, further comprising computer-readable program code means for remembering each item that was in the shopper's possession when the shopper entered an establishment in which a transaction reflected by the transaction receipt was conducted, and wherein the computer-readable program code means for searching and computer-readable program code means for concluding do not apply to the remembered items. 